This invention relates to probes for sensing one or more of a patient's temperature, pulse rate and respiration rate and, more particularly, to such a probe in which the sensing means of the probe are electronic.
It is necessary in providing health care to patients to quickly and accurately determine the patient's temperature, pulse rate and respiration rate. Often, it is desirable to concurrently obtain the values of all three of these vital signs. Traditional methods, such as require the use of mercury thermometers for temperature measurement or the use of watches for respiration or pulse rate, are often less than completely accurate and are too difficult in their execution to permit easy concurrent measurement or rapid measurement.
Accordingly, in recent times, techniques have been developed for measuring these vital signs by electronic means, and probes have been developed which employ these electronic means to concurrently measure a plurality of the vital signs through use of a single probe. An example of such a multifunction probe is shown in U.S. Pat. No. 4,202,353 of Hirsch et al. in which both the patient's temperature and respiration are sensed by thermistors. One thermistor is located beneath the patient's tongue to sense body temperature, and the other thermistor is located in the path of the patient's nasal passageway to sense respiration rate. These sensors are mounted to a mouthpiece which, in turn, is covered by a sheath.
Other mouthpieces for making like measurements are known, and examples may be found in U.S. Pat. Nos. 3,410,264 of Frederik and 3,940,251 of Jones et al. In the Frederik patent, the mouthpiece is used as part of an instrument for measuring total respiratory and nasal air resistance. In the Jones et al. patent, a person exhales through a detachable mouthpiece which provides an electrical output dependent upon the amount of alcohol in the breath sample.
Other sensing means have also been utilized to make measurements of this type. For instance, in U.S. Pat. No. 3,736,918 of Mutschelknauss et al. blood flow in the mucous membranes or the gum of a patient is measured by electronically magnifying the area being investigated to visually ascertain the blood flow velocity. The use of photoplethysmographs for making various blood pressure measurements or the like is also well known.
These probes and the variety of sensing means used in association therewith lack means for insuring that the sensors are properly located within a patient's mouth so that the sensors will accurately sense true temperature or whatever other function is being sensed. In addition, the advantages of fast and accurate measurement obtained from the use of reflective photodetectors for the sensing of pulse or respiration rate have not been realized in such mouthpiece probes.